Birchwood Aluminum Black Metal Finish The room temperature chemical used by gunsmiths and industry to blacken aluminum parts. Restores scratched and marred areas quickly. Fast acting liquid is easy to apply with no dimensional change. Colour will vary from deep grey to black depending on the alloy. Aluminum Black is also excellent for blackening name plates, plaques, trophies and other engraved items. Final appearance can be enhanced by applying wax or oil.